Gas grenades from Cleaners destroy smart cover, Shock grenades (not EMP) from LMB destroy it as well.
If it gets destroyed in this manner then the CD resets.
Personally I have no issues with this, I think it's a decent compromise. In PvP if you want to briefly disable enemies SC then you grenade them with anything, and if you want to deny them then you throw the EMP. The latter prevents recovery of SC by disrupting and preventing skill use. The only problem is that there are so many grenades in total (14 at max capacity excluding FireCrest?) that it would be hilarious...
On the flip side, it's exploitable during PvE, since if the SC goes through it's full duration then it begins it's cooldown, and that makes it more desirable to have it destroyed by grenades...
Hi,
This is currently being investigated.
Thanks
QuB3